Collar for dive tank



FIG. 1 is a bottom perspective view of a collar for dive tank, showing my new design;

FIG. 2 is a side elevational view, the opposite side being a mirror image thereof;

FIG. 3 is a bottom plan view thereof; and,

FIG. 4 is a top plan view thereof. 

The ornamental design for a collar for dive tank, as shown and described. 